SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d506501b8e826ba6819d42c87825f8cc25013bfbc117f8d695b81a5038c8c07' 
  AND token = 'Sj4zAXqQA76wX5em+gXfzuzETGHanmm9bBL6pqv+orY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}